Accession Number:

AD0661496

Title:

THE GROWTH OF WHISKERS FROM VAPOUR PHASE.

Descriptive Note:

Technical memo.,

Corporate Author:

EXPLOSIVES RESEARCH AND DEVELOPMENT ESTABLISHMENT WALTHAM ABBEY (ENGLAND)

Personal Author(s):

Report Date:

1967-01-06

Pagination or Media Count:

53.0

Abstract:

The factors influencing the growth of whiskers from the vapour are reviewed. Reactions are classified as either physical or chemical, the latter being subdivided as homogeneous or heterogeneous. The stages of growth are taken to be i nucleation, arguments being presented that this is normally a surface process, ii growth from the nuclei, critical analyses being made of the screw-dislocation and VLS mechanisms, and of the supersaturation criteria for the physical growth process, and iii termination, about which little is known, but which may be due to dislocation movement or surface poisoning. Metallic and ceramic whiskers resulting from chemical reactions are reviewed, and the E.R.D.E. process for the growth of silicon nitride analysed. Thermodynamic and kinetic criteria for the chemical reaction taking place at the whisker tip are suggested, these criteria being regarded as the chemical analogue to the supersaturation conditions for the physical growth process. Author

Subject Categories:

  • Ceramics, Refractories and Glass
  • Metallurgy and Metallography
  • Crystallography

Distribution Statement:

APPROVED FOR PUBLIC RELEASE